1. Field of the Invention
The present invention relates to a substrate structure of a disk array apparatus, a disk array apparatus and a disk array system.
2. Related Background Art
FIG. 9 shows a front view of an example of a conventional rack-mounted disk array system. As indicated in the figure, depending on the performance and/or specification required, the disk array system is equipped with one or more expansion housings (secondary disk array apparatuses) 110 to expand disk drives, in addition to a basic housing (a primary disk array apparatus) 100 that makes up a disk array apparatus. More specifically, a disk array system is structured by containing the basic housing 100 and the expansion housings 110 inside a rack frame 120. The basic housing 100 and the expansion housings 110 are equipped with boards (substrates) and apparatuses that provide various functions of the disk array apparatus.
Conventionally, in addition to a controller module, a resource management section called an enclosure is provided and a dedicated substrate is used to operate the enclosure as a module. The enclosure has several functions, and one of them is a management function to consolidate the control of access to every hard disk drive module in every housing when a disk array apparatus is expanded by adding one or more expansion housings. In other words, the enclosure collects and monitors management information concerning the status of resources, such as every hard disk drive within every housing. The basic housing (the primary disk array apparatus) is equipped with the enclosure (the resource management section) in addition to the controller, but each expansion housing (the secondary disk array apparatus) is required to have only an enclosure (a secondary resource management section) and does not have to have a controller.
Specifically, as shown in the block diagram in FIG. 8, the enclosure of the basic housing 100 controls switching Of a Fibre Channel Loop (which is also called Fibre Channel Arbitrated Loop (FC-AL)) between a controller 700 and disk drives 200. A fibre loop switching function of the enclosure is achieved by a port bypass circuit (hereinafter called a “PBC”) on a chip. On the other hand, the enclosure (the secondary resource management section) of each expansion housing 110 is connected to the enclosure of the basic housing 100 via a Fibre Channel Loop PBC and lines 60 and 91. This structure allows management information regarding resources such as disk drives 200 of the expansion housings 110 to be collected and monitored.
In addition, the enclosure is wired to be electrically connected to a display lamp device that indicates the operating status of the disk array apparatus, as well as to a power source module and a fan module, which enables the enclosure to obtain data regarding the status of each module and to send control signals to the various modules. In other words, the enclosure has a function to monitor the power source module, a function to control the display lamp device that indicates the operating status of the disk array apparatus, and a function to control the fan module by monitoring the temperature inside each housing. The function to monitor the power source module involves monitoring its running state and on/off control. In FIG. 8, such data and control signals sent to and from each of these modules are indicated as resource management information.
One of the resource management functions of the enclosure of the basic housing 100 and of each expansion housing 110 is to collect data regarding the mounting status of the disk drives 200 and the power source module onto the disk array apparatus, and based on the data to notify the controller of the mounting status.
The various functions of the enclosure described above are achieved by a dedicated LSI, microcomputer or PBC functioning as an enclosure controller section.
Mounting the enclosure of the basic housing 100 in FIG. 8 as a single, independent module has been an impediment to building a smaller disk array apparatus. This is even more true in high-speed transmission such as at 2G bps, where a CDR (clock data recovery) must be added for every few drives in order to maintain waveform quality. Since the number of CDRs that can be added per chip of PBC that realizes the fibre loop switching function is limited, the number of PBCs mounted increases; and this often further impedes the building of a smaller disk array apparatus.